As the Intelligent Transportation System (ITS) technology evolves, more and more information about the traffic situations can be obtained and generated. ITS-dedicated wireless network systems have been developed to support Vehicle-to-Roadside (V2R) communications. For example, in Japan, the ITS spot and Electric Toll Collection (ETC) gate infrastructure based on the Dedicated Short-Range Communication (DSRC) standard using 5.8 GHz band has been deployed nationwide on the highways [1], and the V2R communications for obtaining the information from cars and delivering traffic information to the cars are supported by using the DSRC-enabled onboard unit (OBU) loaded on the cars.
Also, a mobile communication system is broadly deployed, and it is proposed to execute transportation check-in (e.g., ticketing and identification) using a cellular phone [2].
Currently, the DSRC-based V2R communication system and the mobile communication system are isolated and little studies have been made to explore the effective combination of the two communication systems to create new values in terms of enhanced services delivered to the users.